The present invention relates to compositions suitable for use as lubricants and lubricant additives which contain a combination of conditioning agents for preserving the integrity of elastomeric materials, for instance, an ester-substituted hindered phenol antioxidant and a swell agent, e.g., a sulfolane.
Ester-substituted hindered phenol antioxidants are known from, for example, U.S. Pat. No. 5,523,007, Kristen et al., Jun. 4, 1996, and U.S. Pat. No. 6,559,105, May 6, 2003.
Seal swelling agents, including substituted sulfolanes, are known from U.S. Pat. No. 4,029,587, Koch, Jun. 14, 1977.
The present invention provides, among other advantages, a mixture of conditioning agents for preserving the integrity of elastomeric materials, particularly when in contact with lubricants. In certain embodiments, the mixture of agents exhibits synergy. Rubber seals are critically important to the proper operation of many engines, power transmission devices, pumps, gears, and bearings. Preserving the integrity of seals in such devices is desirable, in order to lower the maintenance costs of operation and to prevent unexpected loss of lubricant that could result in catastrophic mechanical failure.